Yanukovych, 68, spoke to the press Wednesday in Moscow, breaking more than a year of silence. He would not endorse any of the over 30 Ukrainian presidential candidates but accused President Petro Poroshenko of plotting vote rigging. He offered no proof for his claims.
"Authorities are going to do everything in their power and use all of its powers, including various tricks, to rig the voting, because President Poroshenko cannot win without vote rigging," Yanukovych told reporters in his first public appearance since 2017.
Yanukovych and his election team were accused of vote rigging during Ukraine's 2004 presidential campaign. He ended up losing the re-run of the presidential runoff after the earlier results were annulled following reports of wide-spread vote rigging in his favor.
Russian authorities have for years relied on Yanukovych to lend legitimacy to their actions both in Crimea and in eastern Ukraine, which have trigged wide-ranging Western sanctions against Russia.
Although Yanukovych has been living in Russia for nearly five years, it is unclear whether Russia has granted him asylum or given him citizenship.
Asked by a reporter what legal status allows Yanukovych to permanently live in Russia, Kremlin spokesman Dmitry Peskov said Wednesday he could not immediately answer that.
Yanukovych fled Ukraine in February 2014 as tensions in Kiev flared up following a deadly police crackdown on protesters demanding that he follow through with an association agreement with the European Union. Yanukovych eventually resurfaced in Russia and was tried in absentia.
At a U.N. Security Council session on March 1, 2014, a Russian envoy had read out a request by Yanukovych to send Russian troops to Ukraine. Yanukovych later said he did send a letter to Putin asking for military assistance, but claimed that that was not an official invitation for boots on the ground.
The 2014 annexation of Crimea triggered hostilities in eastern Ukraine, where fighting between Russia-backed separatists and government troops has claimed more than 10,000 lives.